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Electrical nightmare

1351 Views 28 Replies 7 Participants Last post by  jn.mitchell59
Helllo again. This time, Im at a complete loss. I've spent hours trying to find out why my tempgauge, fuel gauge, shift display, & radio stopped working. Also the charge light is still on, even though it's charging. (The shift display quit about a week before the other stuff did.) I've checked ground points, avd all fuses great and small with an ohmmeter, and pored over diagrams searching for a common point that would tie all this together. I'm considering calling the Belle of Louisville, to see if they need a new boat anchor! Help, pls!!
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dang, and you just got that fuel gauge sending unit working too. Aside from the radio not working, I would think the bulbs could have gone out. I guess you don't mean bulbs though.
I'm assuming you have an analog dash. The only common point I can think of without looking over diagrams is the ignition switch / circuit. It would have to be at least in the "run" position to let the radio turn on. Yet it can be turned off independent of the other lights and gauges. (You do have the radio turned on right?馃Of course you do. 馃檪)
The next thing I can think of is if your charge light is on, then there may be a shorted wire grounding out what I venture to say is the power source to those items. it may not kill your battery while off because it is only getting power while in the run position.
With your shift display, are you referring to just a light is out or do you have some other non analog display?
I like your style. man! This all started when I changed the alt. B+ wire to a much thicker gauge, because I bypassed the factory wire due to extremely high resistance. I've rechecked everything 32 times, and tyhe PRNDL display as well as odometer, went skyward about 2 weeks before. I've been a heavy line tech a bit over 40 yrs., but Satanic elec. issues have never been my forte. What led to the wire change is that I'm no longer able to scamper under a vehicle, and right before the wire change I was mised by not being thorough, so I kinda blindly got a used alternator that took 2 weeks to get here, (Thanks Ebay, NOT) and it still didn't charge. so Einstien here got out the first thing he should have used, a voltmeter. 12v key off, .3v when running DOH! So I made a wire which turned out to be too small a gauge for my liking (got warm). So I went with about an 8 gauge house wire, then the problems started.
Aside from the new information I just gleaned from that, this also reminded me of the voltage regulator directly on the alternator.
Which I don't remember if that was checked in the previous threads.
It does have an internal regulator, just one small wire to the ECU. 40 yrs. heavy line mechanic, but electricity can flummox me, cause I hate to admit I've never really learned it. I figured justb send the worst ones to the electric shop. Same with auto transmissions. Let bthe folks that do it every day do what they do. Appreciate the info there, the next logical step is to somehow get under the damned thing anc check the lone fuse link at the starter, then put the wiring back to stock. Yes, about 3 volts running, and when I ran a jumper from the battery to the B+, 14.3 volts when running. (that was after changing the alternator.) That told me rotten connection at the starter, where bthat wire originated. -Man, if I just had my tools, jacks and stands back.....
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Heavy line mechanic makes sense to me now. I originally thought you meant electrical lineman.
At this point, even if you change that wire back to a stock grade, what ever damage that has been done to cause your gauges to not be working has been done, and will still need to be pinned down.
I'm sure you already knew that, but just in case.
I think what @Sailing_Faith posted above is a good start and maybe even your finish. It fits the bill.
.....But WAIT! Don't touch that dial! lol Another new development. There is now a 12v draw on the battery, stemming fron the 30a BATT Maxifuse. I disconnected the alt. B+ just to be sure, and of course it's still there, even after removingses # 15 and 13, plus the Acc. Power Circuit breaker. At any given time, I'm waiting for a battery of clowns to start emerging from this damned thing!......Oh, and the wire is a black multistrand, although so large a gauge it's difficult to bend.
.....But WAIT! Don't touch that dial! lol Another new development. There is now a 12v draw on the battery, stemming fron the 30a BATT Maxifuse. I disconnected the alt. B+ just to be sure, and of course it's still there, even after removingses # 15 and 13, plus the Acc. Power Circuit breaker. At any given time, I'm waiting for a battery of clowns to start emerging from this damned thing!......Oh, and the wire is a black multistrand, although so large a gauge it's difficult to bend.
Also, by removing that 30 Amp circuit breaker, the Batt and the low fuel lights go out, but it's still charging 14.4
Another thing I'm thinking is your change of your B+ wire may not have anything to do with it, as it goes form the battery directly to your starter then to ground most likely. Admittedly, I had to look up what B+ even was.. (I never heard it before) and I don't really know where your wires run. I'm not looking at a diagram here.
But in that above fix, he had no direct cause for it either.
Gremlins?
Just to help you sleep better. I know you were worried about losing your touch.
Indeed I am, kind sir. The wire just goes over the top of the engine, just like God intended. I have yet to splice in a fuselink, which I will do once I get the correct gauge wire. (Trying to leave nothing to chance).
This new development arose without actually doing anything else? Just randomly tested it and found?
Do you drive this daily?
Sounds like wire insulation has worn away somewhere that it could be going through enough resistance to not blow the fuses. I can't imagine where though at the moment.
Or something is on that is not obvious.
Have you checked into what @Sailing_Faith posted?
Daily, yes. And this new thing just popped up, I've never had a problem with the battery going flat after a day or 2. I just read his message about the cluster board, will probably take it out tomorrow. Also I need to check the pink wire at the headlight switch, looks like it goes to the fuel gauge.I kept the BATT Maxifuse out, just to see.
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This new development arose without actually doing anything else? Just randomly tested it and found?
Do you drive this daily?
Sounds like wire insulation has worn away somewhere that it could be going through enough resistance to not blow the fuses. I can't imagine where though at the moment.
Or something is on that is not obvious.
Have you checked into what @Sailing_Faith posted?
PC board was fine, however there was a green wire at the connector that I couldn't get to stay in, so I "Skippyfied" it, and drove a small screw next to it to hold it in place. Backyard fo sho, but effective. And alas, no change whatsoever!
Keep us posted. Hoping for some luck there, and will be looking. If I come up with anything...
Has to be the ECM. It's the only ytie point for everything affected, caused by too much current via larger than life gauge cable.
I found my draw, awhile back I broke off the hazard button, so I made a plate to cover the switch guts with a screw in the middle to hold what was left in position, and the flasher was working without the light all night, because the screw was out of ,adjustment", lol. ( 0oor man's got poor ways). From what I could tell from the schematic, the fuel and temp gauges are wired into the charging system. I also removed and ohmed the fuel sender, just to be sure. And that damned charge light staying lit.,.....
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Having a larger cable will absolutely not cause a problem with 鈥渢oo much current鈥.

The ECM (our computers are actually PCMs) rarely fail.
Well, shit, it sounded good, lol
If I can obtain the correct info, according to the instrument panel diagram, there seems to be a second voltage regulator for the gauges. And every item that I listed, including the prndl display, goes through this. I have yet to locate it on the vehicle though.
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If I can obtain the correct info, according to the instrument panel diagram, there seems to be a second voltage regulator for the gauges. And every item that I listed, including the prndl display, goes through this. I have yet to locate it on the vehicle though.
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